Improvement in artificial legs



UNITED STATES PATENT OFFICE.

v i GEORGE B. 'I'.IEVETT, OF SALEM, MASSACHUSETTS.

IMPROVEMENT IN ARTIFICIAL LEGS.

Speciiication forming part of Letters Patent N0. 35,937, dated July 22, 1862.

erence being had to the accompanying draw- Y ing, making part of this specication, in which is represented my improved artificial leg, the parts from the knee-joint down being shown in section. Y

The improved artificial leg which is the subject of my present invention is intended to be applied in cases of amputation above the kneejoint, and is so constructed that its length may be easily and nicely adj usted to suit the wearer, it being foun'd in practice to be almost impos-l sible to make an artificial leg by measurement to be comfortable. In all other artiiicial legs with which I am acquainted the spring which is applied at the knee-joint to straighten the leg when bent continues to exert its full strength when the wearer is sitting down and the thigh and lower leg are at right angles to each other. This is inconvenient, as the wearer is compelled to extend the leg instead of holdingit bent in a natural position. This I have remedied by my improved construction of knee-joint and the manner of applying the spring thereto.

That others skilled in the art may understand and use my invention, I will proceed to describe the manner in which I have carried it out.

In the said drawing, A is a straightslick of some strong wood, (which represents the tibia ofthe human leg,) to the lower end of which is hinged the foot-piece B, to which a certain amount of motion is allowed, as follows: the foot-piece B has attached to its top an iron plate, a, to which is hinged at b two metal straps, o, (shown detatched in Fig. 2,) which are attached by suitable bolts or screws, one on each side of the piece A. A spring, C, is placed behind the piece A and presses against the heel of the foot and against a stop, d. As

the weight is thrown upon the heel,this spring iscompressed, and as the step is completed a shoulder, e, on the front side of the piece A comes down onto an elastic pad, t', secured to the top of the foot-piece B, and limits the vibration of the foot on its pivot b. The thickness of this pad t may be varied to suit the length of step or stride of the wearer.

To the upper end of the piece A is attached, by bolts or screws, two metal straps, f, one on each side, (shown dotted,) to which is pivoted a metal spindle, D, on one end of which is cut a screw to receive a nut, g, and from the other end of which projects a plate, h, which, when the leg is straightened out, comes in contact with and rests on a pad, m, of leather or other yielding material, attached to the top of the piece A, which limits the motion of thejoint in one direction. This pad may be varied in thickness, so as to give a proper and natural movement to the leg. A block of wood, E, is

attached to thespindle D,which passes through v Its outer side is circular and has a band It is also it. of metal, l, secured to it by screws. screwed to the plate h. pad, n, at the back of the piece A, against which a shoulder on theblock E strikes when the leg is brought into the position shown in the drawings. A spring, F, of elastic web bing or other suitable material,is connected at one end by a strap, o, of leather, to the metal wearer may sit down with his leg bent in a natural position without an effort being necessary to resist the power ofthe spring. The socket H, into which the stump is inserted, is connected with the spindle in the following manner: A circular block, G, of wood,is'

slipped over the spindle D, and a metal sleeve or cap, r, with a nut, g, in its 'topfrits over the block and screws down onto it-,the screw on the the spindle turning in this nut. From this sleeve braces s (shown dotted) are connected with the metal shell or socket H. Two locknuts, 5 and 6, secure the parts when screwed down.

The block G may be changed for one of a different length, or a piece may be eut oft' from it to adjust the leg to the proper length,

There is also a soft' the socket being screwed down farther onto the spindle D. A soft pad or packing, O, of stuffed leather or other suitable material,is inserted in the shell H to receive the stump of the limb. rIheholesaare for Ventilating the socket', and the buckle fu for strapping it to the body. A metal ring, x, is attached at the head of the piece A, and a block, 1 surrounds it near the middle of its length. A covering or padding of canvas may be stretched over these to give shape to the leg, and a block or pad (not shown in the drawing) forms the instep of the foot, and a rounded block on each side of the knee,together with the curve ot the block E, gives to it a natural shape.

The pad O in the socket H may be changed in size or form to t the leg of the wearer. This is particularly necessary, as the stump is liable to shrink away.

The above-described leg is light and of great strength, and from the simplicity of its several adjustments and the manner of applying the spring to the knee-joint is remarkably easy and satisfactory to the wearer.

Vhat I claim as nly invention, and desire to secure by Letters Patent, is

1. The ieg-piece A, to which the foot B is hinged at one end and the spindle D at the other, substantially as described.

2. The shoulder e and pad t' for limiting the motion of the foot B, substantially as specied. 3. The block E, with the spring F attached to its front in the manner substantially as set forth.

4. Connecting the socket H to the spindle D, in the manner substantially as specified,

GEO. B. JEWETT.

'Wi tnesses:

Trios. R. Renon, I. E. TEscHEMAcHER. 

